Case Presentation:  

Peter is a 6 year old Havanese who lives in Lincoln County Maine and leads a very happy and normal life with his loving people.  He enjoys long walks but is always on a leash and well supervised.  He was born with an abnormal vessel bypassing his liver (portosystemic shunt) and had surgery to correct that years ago.  He recovered from that and has been a normal dogs since then until this past Fall at which time he came into our Emergency service with a 2-3 week history of progressive vomiting, diarrhea and decreased appetite. He was initially treated supportively with his primary vet for possible pancreatitis but did not improve at which time full blood testing was done and revealed he was in kidney failure and had a low platelet count.  He was referred to PVESC for ongoing care.  He was admitted and treated with IV ampicillin and supportive care.  An ultrasound was consistent with an acute kidney disease such as Leptospirosis or other bacteria.  He improved with IV fluids and antibiotics (Unasyn) that would cover for many infections (broad spectrum) and was discharged with a plan for close monitoring.  His initial Leptospirosis testing was done on both urine and blood to screen for the organism’s DNA in both fluids – imagine a lake either full of fish or containing only few fish and that pulling a bucket out without a fish does not mean there are not fish, just that maybe there are only a few fish.  Leptospirosis can cause significant infection without a large amount of organism detected in blood and urine so negative testing at this first stage does not rule out Leptospirosis.  Regardless, Peter had recovered enough for his people to take him home for ongoing care and time.  He was improved at home but still having some increased water intake, lethargy and inappetance.  At reassessment with his primary vet he was determined to have progression in his liver values and stable kidney values. Due to concern for ongoing infection he came down to be assessed through internal medicine. Despite his clinical improvement he continued to drink excessively and have periods of lethargy.  We opted to do a different test for Leptospirosis that looks for the body’s response (antibodies as he had been sick for a few weeks and should have had time to show us more clearly if his signs were all related to Leptospirosis.  This testing was severely elevated so he was treated with a second antibiotic that can get Leptospirosis out of the tissues better than his initial course would have.  Peter has gone on to make a nearly complete recovery with normal kidney and liver values.  He has a very small amount of protein spilling into his protein we are currently monitoring and is likely a result of this infection.  We will watch him closely and help his kidneys and Peter live his best life!  

Canine leptospirosis
Canine leptospirosis is a serious bacterial infection that manifests in a number of different ways in dogs and is contagious to humans. Any dog who enjoys the outdoors is at risk for contracting Leptospirosis. In Maine our winters make it much more difficult to contract in the colder months so we see it more frequently Spring through the Fall.  Prevention of leptospirosis includes vaccination, which protects against the four most common strains, and avoiding common sources of contamination.

Transmission
Leptospirosis is found throughout the United States and is more prevalent in certain regions. The bacteria loves warm wet environments and can survive weeks to months given the right setting.  Heavy rainfall and high levels of humidity enable it to spread more easily.  Dogs most commonly contract the disease by exposure to water contaminated with wild animals’ urine, especially stagnant or slow-moving water like puddles, ponds or lakes. A number of different animals are able to spread the bacteria through their urine, particularly small mammals like rats and racoons but also some livestock.  The bacteria gains access to the body via broken skin (cuts/mucous membranes) or through ingestion. Typically the signs of disease develop about 7-10 days following exposure.

Clinical signs
Leptospira attach to the cells that line blood vessels (endothelial cells) causing inflammation and trouble making normal clots.  It spreads throughout the body and can affect multiple organs – the liver and the kidneys are often affected. Interestingly, Leptospirosis can cause a very wide range of clinical signs and severity of disease ranging from a fever that is self limiting to severe and multi-organ failure requiring supportive measures such as dialysis therapy for the kidneys. Leptospirosis can be life-threatening.

Additional signs may include: dehydration, yellow pigment in the eyes or gums (icterus), bruising, trouble breathing, severe ocular inflammation (uveitis).

Diagnosis
Definitive diagnosis of this Leptospirosis can be very challenging due to the wide range of clinical signs that can often resemble numerous other diseases and vaccination causing issues with testing.  Diagnosis can be made with a combination of testing of the urine and the blood (PCR which is looking for DNA from Leptospirosis) and/or looking for the body’s response to the infection (antibody testing).
Leptospirosis is treated with antibiotics and in many cases is cleared with 2-3 weeks of Doxycycline (an antibiotic). Depending on the severity of the case, other supportive measures (IV fluids and anti-nausea medications, nutritional support, blood pressure monitoring and management, liver protective treatments, etc.) and hospitalization can be required.

Some cases even require dialysis therapy which is not available for animals in the state of Maine.  We generally refer those patients to Tufts Veterinary School in Grafton MA. Dialysis “buys time” for the kidneys to recover enough function however many of those dogs will have chronic kidney disease long term.

Outcome
Leptospirosis carries a fair to guarded prognosis – most cases resolve with the course of antibiotics and recover fully.  Some animals will recover but struggle with either chronic kidney or liver issues. We have many ways to help them with those issues should they develop.  Some dogs do not survive due to acute and overwhelming multi-organ damage. Dogs who develop respiratory signs (breathing difficulty) are less likely to survive.

Leptospirosis is one of the infections that is zoonotic – this means it is able to spread between mammals, so from dog to human or human to dog. Generally, within 72 hours of antibiotics it is very difficult to contract this bacteria from a dog undergoing treatment – wearing gloves, thoroughly washing hands and using good cleaners can prevent infection.

As with many diseases prevention is much better than the treatment and is multimodal.  Vaccination can protect the dog and reduce human exposure.  After the first series it is required once yearly to remain effective.  If more than a year passes between vaccination the initial series is restarted. Additionally, minimizing exposure to stand/slow moving water and wildlife can be helpful.

Authored by: Alice Benedict, DVM, DACVIM (Internal Medicine)